1. Technical Field
The present invention relates to a flow channel member, a liquid ejecting head, and a liquid ejecting apparatus and, more specifically, to a flow channel member provided with a flow channel in the interior thereof, a liquid ejecting head, and a liquid ejecting apparatus.
2. Related Art
As a representative example of a liquid ejecting head configured to eject liquid droplets, an ink jet recording head configured to eject ink droplets is exemplified. For example, an ink jet recording head including head bodies (head bodies each including a head case, a flow channel unit, and an oscillator unit) configured to eject ink droplets from nozzle openings, and a common flow channel member configured to supply ink from ink cartridges as ink supply sources fixed to the head bodies and including ink stored therein to the respective head bodies is proposed.
According to the ink jet recording head configured as described above, ink in the ink cartridge is supplied to the head body via an ink flow channel of the flow channel member. The flow channel member includes an air bubble trap configured to store air bubbles contained in ink and a filter provided on the downstream side of the air bubble trap, and a problem of clogging of the filter with the air bubbles, which may reduce the effective area of the filter, is restrained by trapping the air bubbles by the air trap.
However, since the air bubbles in the ink flow channel are gradually grown and are increased in size, the air bubbles which are excessively grown need to be regularly removed.
Accordingly, in the ink jet recording head of this type, a cleaning operation which generates an ink flow having a velocity several times higher than the velocity at the time of a printing operation is regularly performed to discharge air bubbles in the ink flow channel. In contrast, as a configuration which is capable of discharging air bubbles mixed into ink by a method other than the cleaning operation, there is proposed a configuration including a gas-permeable film provided on a side surface of a common liquid chamber which communicates with a pressure chamber of a head body, and a chamber provided on the side of the gas-permeable film opposite from the side which comes into contact with ink, in which generation of air bubbles in the pressure chamber is restrained by generating a negative pressure in the chamber to deaerate the ink in the common liquid chamber (JP-A-2006-95878).
However, with the configuration described in JP-A-2006-95878, since the deaeration is not achieved by allowing permeation of the air bubbles in the common liquid chamber through the gas-permeable film unless a large pressure difference is set between the interior of the common liquid chamber and the chamber, a large scale of a depressurizing unit is required for obtaining a sufficient deaeration capability. In addition, if the pressure difference is too large, the ink loses moisture mixed and hence the viscosity of the ink in the ink flow channel is increased. Therefore, control of the pressure in the chamber while monitoring by using a pressure gauge or the like is required. There is also a problem that the gas-permeable film formed of a fluorinated thin film or a silicon-based thin film is reduced in transmissivity if the ink bleeds. Furthermore, when the deaeration is not achieved sufficiently in the common liquid chamber and if the air bubbles is mixed in the ink flow channel inadvertently due to loading or unloading of the ink cartridge, and the air bubbles may enter the adjacent pressure chamber before being blended in the ink, which may cause a problem.
Such problems exist not only in the ink jet recording head, but also in the liquid ejecting head which ejects liquid other than ink, and also in the flow channel member used for other applications other than the liquid ejecting head.